Corybas Pollinators

Rudie Kuiter’s Short Paper 5, October 2017, is about he and his team’s observations on the pollination strategies of fungus-gnats with Corybas. A small section from the introduction is quoted below:

Certain flowers in large colonies were most popular over several days and both sexes were observed feeding on the boss, which suggests a food-related attraction. Virtually nothing was known about the Corybas pollinators and primary literature to date only offered hypotheses. Based on our findings, the persisting statement in literature that ‘Corybas species attract fungus-gnats as putative brood-sites’ is incorrect for the taxa in Victoria. No evidence of ovipositing in flowers was found. Females feeding looked gravid and were presumed to be unfertilised. All individuals looked fresh with undamaged wings and it was apparent they had recently hatched.

Is this a hypotheses that needs revising? Rudie definitely demonstrates the importance of careful and meticulous observations.

Click here to read the full article

Corysanthes diemenica 077
Corysanthes diemenica (Veined Helmet Orchid)

Notes on Dipodium pardalinum at Silverton

A site, along Rarkang Rd, Silverton, leading into Talisker Conservation Park, was visited on December 29, 2012, January 2, 2014, January 16, 2015 and January 9, 2017.

In the earlier years about 20 specimens of Dipodium pardalinum were found with 18 (plus 3 beheaded) in 2015.  A small number of D. roseum was located in 2012, none in 2014, one in 2015 and none at all in 2017.

In 2017 there was bumper crop of D. pardalinum and Ed Lowrey, Helen McKerral and I counted 124 flower spikes.  This may represent only 122 plants because in two instances there were two spikes emerging from one tuber (see image).  It is possible that other closely placed flowers were also growing from a single tuber. This same phenomenon was observed in two cases, with D. roseum, at Hender Reserve, Stirling, on January 12 this year.

All spikes of D. pardalinum this year were found on the verges of Rarkang Road or nearby inside private property in small holdings, with houses, adjoining the road, apart from two spikes only, just inside the Talisker Conservation Park, where Rarkang Road heads into it.

The genus Dipodium is much more varied than I realised.  Our DVD, South Australia’s Native Orchids, only deals with the ‘leafless saprophytes, mycophytes or hemiparasites’.  If you go to ‘Native Orchids of Australia’ (Jones, 2006), you will find that among the terrestrial species there are both leafless species (as with the local D. pardalinum and D. roseum), that are impossible to cultivate and one species with leaves (D. ensifolium), found from Cooktown to Ingham, in Qld.  It is easy to grow in a pot.  Bob Bates told me that it is grown here in Adelaide, preferring a heated glass house, but has been grown successfully in gardens.  And then there is a leaved species, D. pandanum, of limited distribution in Qld, that can be either terrestrial or epiphytic, growing up to 5 m in length.  Old pieces that break off and fall to the ground, nestle in the leaf litter and put out new shoots that eventually climb into the trees.  It is easy to grow in a pot (in the right climate).

Leo Davis.

Dipodium pardalinum.
Rarkang Rd, Silverton, Jan 9, 2017.
 d-pardalinum

 two in one spike.jpg Two spikes of Dipodium pardalinum emerging from one tuber.

Rarkang Rd, Silverton, Jan 9, 2017.

A clump of Dipodum pardalinum spikes with at least two emerging from one tuber; see photo above.

Rarkang Rd, Silverton, Jan 9, 2017.

 Pardalinum spike.jpg

 Roseum and Pardalinum.jpg

Dipodium pardalinum (labellum white with dark pink spots) growing intertwined with D. roseum, (labellum pale pink with dark pink stripes).

Rarkang Rd, Silverton, Dec 29, 2012.

 

It’s Not Extinct at Ferris-McDonald After All

Leo Davis is an enthusiast about the natural world and shares his knowledge through different journals.  He is a keen observer and meticulous in his record keeping.  He is also very knowledgeable about orchids.  The following is one such article of Leo’s.

GOOD NEWS FROM FERRIES-McDONALD CONSERVATION PARK
Leo Davis

I was aware of the Star Spider Orchid from Bates who lists the species as ‘3E, critically endangered in South Australia, nationally rare’ (pp. 242–243). I knew that in the past it had been found at Monarto and Hartley and discussions with members of the Native Orchid Society of SA (NOSSA) suggested that it had been seen at Ferries-McDonald Conservation Park, but was now possibly extinct there. My searches over five years had all failed.
On August 2, 2014, I ran into, then strangers, Len Stephens and his grandson Rickey Egel, in Monarto C.P. They had just come from Ferries-McDonald C.P., about 8 km further south. Rickey, who has a very good eye for spotting orchids, showed me an image, in his camera, of ‘the common spider orchid’. From my hurried glimpse I knew immediately it was far from ‘common’ and told him so. I headed straight for Ferries-McDonald C.P. for the first of many fruitless searches.  On August 14, 2015 Rickey and Len showed me a few Star Spider Orchids in flower at Ferries-McDonald C.P. Because I was to lead the Botany Group of the FNSSA on an outing to Ferries-McDonald C.P. on September 5, I had been visiting the park almost weekly and so was able to spend many hours looking for the orchid. It is difficult to spot, being quite small. This year’s plants, perhaps not typical given the very dry June, are between 8 and 20 cm high with flowers only about 35 x 30 mm.
Plants were only found in Broombush (Melaleuca uncinata) associations. As soon as Eucalyptus species were present the orchid was no longer found.
Any survey, especially by a single person, will produce a lower count than the actual population. Leaves of non-flowering or beheaded (the fate of so many spider orchid flowers) plants will not be recognised, some flowers will not be spotted and some plants will flower before or after surveys, with some areas surveyed on different days. Between August 14 and September 5, 2015 just 18 flowering plants (Fig. 1) were positively identified (about the same number of likely leaves and buds, adjacent to these, were noted) over a narrow area of approximately 3,000 m2. The area searched was very much greater than this. Small as this tally is, it establishes a significant population other than the only other South Australian one that I know.  That is on the private property of farmer […], at Hartley. With his kind permission I have counted over 100 flowering plants there during five visits from July 28 (buds only) to August 30 (Fig. 2). The actual population will be larger because I did not cover all of that location. My observations suggest the populations I know to be around 150 to 200 plants with other occurrences probably existing around Monarto and Hartley.
Why have I avoided the scientific name? Many of you will follow the Electronic Flora of South Australia which lists the Star Spider Orchid as Caladenia stellata, as does Backhouse (pp. 456–457). I prefer to follow Jones (p. 76) (who does not recognise the species occurring in SA) and Bates (p. 242) (who says it does occur in SA), both of whom call it Arachnorchis stellata. Backhouse points out that the nearest other occurrence, the major one, is in central southern New South Wales, south of Rankin Springs, several hundred kilometres away, and that the plants there differ from our populations in having smaller flowers. He suggests that we are looking at a separate undescribed species, Caladenia sp. ‘Murray mallee’ (p. 484), but that it might indeed be co-specific with the Rock Star Orchid (sic), Caladenia saxatilis, which is similar and occurs further north, in the northern Mt Lofty and the southern Flinders Ranges. Bates told me in conversation, that he disagrees with Backhouse and believes the local plants are the same as those in NSW and distinct from A. saxatilis, which grows in soils of different pH (acidity).

 

Good News from Ferries-McDonald-1 38LD
Fig 1: Arachnorchis stellata, Ferries-McDonald CP,  August 22, 2015.  Photo: Leo Davis

Good News from Ferries-McDonald-2 38LD
Fig 2: Arachnorchis stellata Hartly, South Australia, August 5, 2015.  Photo: Leo Davis

BIBLIOGRAPHY:

Backhouse, G. (2011). Spider-orchids – the genus Caladenia and its relatives in Australia. DVD/pdf, Backhouse, Melbourne.
Bates, R.J. (2011). South Australia’s Native Orchids, DVD, NOSSA, Adelaide.
eFlora SA. Electronic Flora of South Australia; last updated August 22, 2015.
Jones, D.L. (2006). A complete guide to native orchids of Australia including the island territories. Reed New Holland, Sydney.

 

 

Used by permission, extract from The South Australian Naturalist Vol. 89 No 2 July-December 2015.

Orchid Walks at Mt Lofty Botanic Gardens

For the last couple of years, NOSSA has been conducting spring tours at the Mt Lofty Botanic Gardens, South Australia, showcasing our beautiful native orchids to visitors far and wide.  They have come from not only Adelaide but from interstate as well as overseas from such countries as America, Germany, England and many others.  If you are planning to be in Adelaide during spring, then consider joining one of our walks, but for those who cannot attend here is a video for you.  So watch and enjoy …….

 

2011 POST FIRE SURVEY – MESSENT CONSERVATION PARK

Cathy Houston

Conducted by the Conservation group of the Native Orchid Society of South Australia Inc. for the Department of Environment and Natural Resources.

Members of the Native Orchid Society of South Australia and two volunteers conducted a three day orchid survey of Messent Conservation Park, following a prescribed burn that took place in March/April 2011.

The survey in burnt areas was undertaken from Friday 9th – Sunday 11th September, inclusive. A maximum of eleven people took part, not all being present for the entire survey time. Participants worked in pairs (or threes if numbers dictated such) and conducted ramble surveys within very rough grid areas of about 500 meters square. Because of the size of the burn area and access difficulty, none of the internal area was surveyed. However, many habitats were covered and extrapolation could predict what would be likely to occur in these areas. Some other vegetated areas were visited as well. These included flats covered in rushes, or sedges and rushes, a 16 month old prescribed burn area, a Pink gum (Eucalyptus fasciculosa) rise, mallee woodland and a Banksia herb-land.

Observations were taken of species present, numbers and any other detail of note, together with GPS location. A numbering code was used for most species.

The results were somewhat variable, presumably dependent on habitat types and their orchid population prior to the burn, the temperature of the burn and to a lesser extent, the emergence or otherwise of orchids prior to the time of burning. For instance, only one small population of Corunastylis (Genoplesium) was noted, this being a species that would have been flowering at the time of the burn. Similarly, no Eriochilus were observed in the survey area. However, Leporella fimbriata which emerges at a very similar time was present in some very large colonies.

The most abundant orchid by far was Pyrorchis nigricans. It was encountered in nearly all habitats of the survey area, the only exception being limestone ridges where it rarely appeared. Flowering had been promoted by the burn with perhaps about half the population in flower/going to flower. Density of the population fluctuated but it seemed to be consistently present. However, its absence was noteworthy from an area of burn undertaken in May 2010. The habitat was ideal for the species and given the proliferation throughout the 2011 burn one would have to speculate about the timing of that burn on that (and perhaps other) species. Very few species were located in that area at all. It has to be said in fairness though that the only Thelymitra epipactoides found in any burn area was seen in this 16 month old burn.

Perhaps the most orchid-rich habitat with regard to number of species was the limestone ridges. Some of the open flats had the least diversity. It was not easy to ascertain what the dominant vegetation had been in these areas. Conversely some of the flats had a good scattering of orchid species, the numbers of each being relatively low.

Winter flowering species were conspicuous by their low representation.  No Bunochilus (Pterostylis) were seen, few Urochilus (P.) sanguineus, Diplodium (P.) dolichochilum, Acianthus pusillus, Corysanthes (Corybas) species and Cyrtostylis robusta were seen in the burn area.  The only exception was Linguella (Pterostylis) sp. Mallee. It was encountered in small to medium sized colonies throughout the area, usually with a reasonable number of capsules developing. In a vegetated location Diplodium species was seen in good numbers.

Threats to orchids were minimal. Rabbits were present in noticeable numbers along the northern boundary. Similarly, there was some weed incursion along the northern boundary, Capeweed and one other being the main ones seen. Some predation was observed within the burn area, but nothing we would consider notable. Rabbit activity was also very evident in a flat/Pink gum rise on the track leading south to the boundary. Deer prints were observed throughout the areas we covered. A small flock of sheep encountered in the north eastern sector is of concern. They had free access to the park via a “kangaroo door” under the boundary fence, something they negotiated with ease when disturbed by a vehicle.

Species of significance were Thelymitra matthewsii and T. epipactoides, these both being nationally threatened species. Historical records existed for T. matthewsii from this park, but it had not been observed for decades, despite intensive searches having occurred following the 2002 burn. Some of this surveys records bear a similarity to historical records but since the latter were recorded prior to accurate global positioning systems it is uncertain about the actual locations. This species was encountered as mainly individual plants in about six different locations, usually in very low numbers. Some plants were just leaf but others were seed capsules. All but one group were located in burn areas, the species being very difficult to observe without the removal of much vegetation. It was noted that some of the area where the species was seen had been slashed. It was felt this could be beneficial to them. Observations in the lower South East seem to reflect this type of disturbance is beneficial to T. matthewsii and Thelymitra in general.

More than 60 plants of T. epipactoides were located in one area of a few hundred meters squared, with the exception of the aforementioned one plant in the 16 month old burn. Despite searching of hectares of similar sedge/rush-land, no others were located. Here again, it was thought that some random slashing of this habitat may benefit orchids that like the open areas, viz. Thelymitra, Diuris sp. Short tailed, Glossodia major, and some Caladenia species.
Present in low numbers on the limestone ridges was Arachnorchis (Caladenia) tensa, another nationally threatened species. Despite its national rating this species is more prolific in South Australia.

Another orchid that appeared in considerable numbers and most habitats was Arachnorchis (Caladenia) sp. South East. It grew as single or few plants right up to sizeable collections of plants, sometimes with up to about 50 in a group. Diuris sp. Short tailed was widespread and moderately common. Glossodia major was encountered as mainly single plants widely scattered. Caladenia carnea was in very high numbers under fairly dense mallee on the northern boundary. Microtis species when it was encountered, was in colonies with high numbers of plants. As a generalisation, Thelymitra were absent or in very low numbers. Exceptions to this were T. antennifera and T. benthamiana which were usually seen in very low numbers but widespread throughout the burn area. It was interesting to note that few of the latter were likely to flower, which contrasts with the 2002 burn when flowering was prolific.

One species promoted to flower by the burn was Prasophyllum elatum. It was widespread in most habitats, but not often in the flats. Plants varied tremendously in size and stature with some quite small plants flowering/going to flower. Predation of the leaves was relatively high, with nearly all being chewed down to between 100 to 150 mm. Buds were emerging from the open top of the leaf, instead of emerging from the side of an intact leaf. There were other Prasophyllum species present, but the survey was just too early to identify what these are likely to be. Most of these were found on the limestone ridges.

The orchid list held by NOSSA for Messent Conservation Park prior to this survey must have been somewhat limited because the number of species on our list has now been doubled. With the rediscovery of T. matthewsii in several locations within the park, the other two nationally threatened species present and the expanded knowledge of orchids within the Park we must consider this was a very successful survey. We thank DENR South East for making this survey possible.

Murray Mallee Midges Autumn 2011

R.J. Bates May 2011

The title of this article refers of course to mallee midge orchids of the genus Corunastylis which have been poorly understood.

Summer and autumn 2011 saw good rains across the Murray Mallee from Pinnaroo to Renmark and thus NOSSA members took the opportunity to study mallee midge orchids in flower in March and April.  The results are summarised here.

Corunastylis sp. Box Flat
Ngarkat Conservation Park
Photo: June Niejalke

Aims:

  1. To match species to habitat.
  2. To assess the distribution and population of each species.
  3. To take images of all species.

Midges were found all the way up to Chowilla sand hills, which are just north of the River Murray.  Almost every patch of mallee eucalypts seemed to have some Corunastylis species but an understanding of their ecology was needed to find the flowers.  Degraded or weedy mallee did not have any midge orchids, nor was hard clay, loose white sand, bare trampled soil or dense ground cover worth searching as midges are very small plants and easily crushed, covered up or sand blasted.

Flowering plants were found mostly in the leaf litter under mature mallee, often with associated patches of native pine or circles of Triodia sp. (porcupine grass).  Areas with extra water run off and disturbed soil along road corridors seemed to have produced localised population explosions.  A 4WD vehicle proved handy for reaching remote corners of larger parks like Billiat Conservation Park near Alawoona.

The most common species was the red and green flowered mallee midge Corunastylis tepperi while the similar but purplish Corunastylis sp. Intermediate came in second.  Next came the black midge orchid C. nigricans which seemed to have finished in early March and were found mostly in capsule.

Species of the Corunastylis rufa complex were mostly found in the southern fringes of the mallee.  Their classification is ambiguous seeing Australian orchid expert D.L. Jones says Corunastylis rufa is confined to NSW.  The un-named species of the complex seen included Corunastylis sp. Dark midge and Corunastylis sp. Narrow segments.

Corunastylis tepperi
Alawoona
Photo: Rob Bates

In any case, no fringed labellum species of any kind were observed, so all mallee midges belong to the C. nigricans and C. rufa complexes.

Tiny fruit flies of several species were seen working the flowers but we could not tell if each midge orchid attracted a different fly as the flies are too small to compare!  I suspected that specificity of pollinators is low as apparent hybrid midge orchids were noted.
Recognising the different mallee midge orchids:

  1. If the flowers are bright green and the labellum is rounded, deep purple or maroon then it will be C. tepperi, also known as C. fuscoviride.  The latter is a better name as it means bright dark and green.  C. tepperi has a narrow spike of many tiny flowers.  The finished flowers and capsules will take on a yellowish look.
  2. If the labellum is rounded and the flowers are mottled brown to wholly purple-brown, except for white or white striped petals, the species is C. sp. Intermediate.

DNA studies may be required to check the species limits of the many taxa found.
It is doubtful that such a good display will be found next autumn!

Many thanks to NOSSA members who sent me images of mallee midges recently, especially June Niejalke.

Unknown member of the Corunastylis rufa complex
Carcuma Conservation Park
Photo: June Niejalke
Corunastylis sp. Intermediate
Billiat Conservation Park
Photo: Rob Bates
Corunastylis sp. Narrow segments
Keith
Photo: June Niejalke
Corunastylis nigricans
Karte Conservation Park
Photo: June Niejalke
Corunastylis sp.
Monarto
Photo: June Niejalke
Corunastylis sp. Dark Midge
Ngarkat Conservation Park
Photo: June Niejalke
Corunastylis tepperi aka C. Fuscoviride
Pinnaroo
Photo: June Niejalke
Corunastylis sp. Intermediate
Lameroo
Photo: June Niejalke

An Eriochilus study in the Southern Flinders Ranges: 2010

R. Bates

Until  2009 when NOSSA did an orchid study of Wirrabara Forest Reserve the parsons bands or Eriochilus were thought to be rare in the Flinders Ranges, but that year Eriochilus were found all the way north to Mount Remarkable and were often seen as locally common.

In 2010 I did two visits, one in April and one in May to see how well they flowered after a wet spring the previous year.

Results: all colonies at Wirrabara flowered spectacularly in April 2010 but at Mt Remarkable flowering was poor.  No leaves were visible at the time.  The flowers were white with some strong colour and stems were quite bristly, see image. At Wirrabara plants were sturdy with up to four flowers per scape yet at Mt Remarkable plants were spindly and flowers mostly single.

It was thought that the reason for this difference lay in the wet spring of 2009 at Wirrabara with much less rain at Mt Remarkable.

The second visit in May showed a different picture. Very little rain had fallen at Wirrabara in autumn and the stems of all plants had hardly elongated.  Yet seed capsules were plentiful.  In contrast, Melrose near Mt Remarkable had received good autumn rain and stems there had doubled in length.

So it seems that the number of flowers and strength of plants depends on rain the previous season whilst height of stems depend on rain during the current flowering season.

Curiously, in both areas a second flush of flowering occurred in May with the second flush at Wirrabara producing tiny flowers on short spindly stems (see image) while those at Mt Remarkable had larger flowers on tall stems.

Flowers seen in both areas were similar in appearance and both had leaves which were large, apiculate, dark green, ribbed and hairy above, purple below.  Both the April flowered and May flowered plants belonged to the same taxon and clearly flower size and number, and scape length, are not useful in separating species as they are so variable.

On the other hand leaf shape, texture, ribbing and colour below are important in identifying the species as these are constant features.

Conclusions: only one species of Eriochilus occurs in the Flinders Ranges and this is the same as the common woodland species in the Mt Lofty Ranges.  This species has never been named officially but is generally known as Eriochilus sp Hills woodland and is best identified by it’s leaf … see image.

This is the most common of three or four Eriochilus species in SA.

Leaf of April flowering Eriochilus at Wirrabara dwarfing later May flowered
plants behind it.

Eriochilus species Hills near Mt Remarkable in May 2010

Surveying in the South East

Cathy Houston

In recent years a number of N.O.S.S.A. members interested in field work have been involved in surveys for orchids. These include surveys for individuals as well as government or semi-government organisations.

Late in March this year we undertook an Autumn survey of a forest in the South-East known as The Marshes.  As the name suggests the area is well served with swamps as well as forest of Stringybark with sandy soil.  Several members met the day before to check some areas in the upper SE.  Here in sandy-heath there were two species of Corunastylis in flower, often not very distant from each other, but each favouring different habitats.  In the heath were C. aff. rufa in flower and capsule.  In mallee open forest C. tepperi had recently commenced flowering.

In areas dominated by granite outcrops were found Eriochilus cucullatus flowering and perhaps another un-described Eriochilus species.  Leaves were not present, so no distinction could be made from flowers alone.  However, in mallee the flowers were larger and supported on much taller stems.  Those on the granite were small flowered on short stem, there being no apparent difference in the flowers themselves.  Here also the C. aff. rufa was seen in flower and capsule.

In the lower SE a sojourn into Honans Native Forest Reserve produced yet different species, some in flower.  C. ciliata was already in capsule, the distinctive greenish-yellow lateral sepals still evident and under magnification hairs could be detected on the labellum.  C. despectans had the very last flowers on the top of the scape as well as capsules on earlier flowering specimens.  Speculantha obesa had just commenced flowering.  In most cases the inward facing, smallish flowers had only the bottom one open with buds on the stem above.  Rosettes were not yet present. We were amazed to find Pterostylis nutans rosettes already emerging.  A little less surprising was Leporella fimbriata, but the number of flowers seen at this early stage was few.

The Marshes is not renowned for being prolific in Autumn flowering orchids but our visit was scheduled to try to locate as many as we could.  By the second day we were rewarded with the discovery of plenty of Spiranthes alticola, which were represented in most of the swamps in the western sector.  It is interesting to note that years ago they were found prolifically in the eastern sector but this appears to have dried out too much for them these days.  S. obesa was found in very low numbers and this time one of the plants already had a capsule.

Perhaps the greatest excitement was afforded when two members thought they found Cryptostylis subulata leaves.  All the surveyors collected for lunch and soon were down at the site considering if the leaves lived up to the name.  Much discussion ensued.  If only there was a flower to confirm the diagnosis.  After what seemed like an age a “tired” flower was located!  C. despectans had previously been recorded for the forest and a considerable amount of time was spent in searching known locations but to no avail.  Not Autumn flowering but the other orchid found was Dipodium roseum which was heavy with capsule.  Some of the stems had up to eight large pods hanging on them.

At Mt. Lyon Native Forest Reserve we were able to view many Cryptostylis subulata in flower and capsule.  Another trip was made to Honans to locate C. subulata from provided GPS readings.  After a bit of interesting navigation both swamps were located.  However we were unable to find the target species, one swamp appearing to now be too dry to sustain this species.

A quick trip was made to Telford Scrub Conservation Park following one of the survey days.  Here we saw Eriochilus sp. in flower.  This time they were large flowers with tall, almost robust stems.  Leaves were yet to emerge.  Another surprise was to await us here.  Bunochilus spikes were well up and it was evident there were two species represented.  Some of the spikes were quite pinkish with leaves still tightly furled on the spike.  Flowering will clarify more for us; some of the spikes will have a long growing time.

Upon completion of the surveys some members headed for Piccaninnie Ponds Conservation Park in yet another attempt to locate Eriochilus in flower.  This time we were successful.  It is a long way to travel when not knowing the exact flowering time for the area, and those times can change with each season!  On short thin stems, small flowers with still the same general appearance were what greeted us.  There were buds and capsules present as well, but most interesting to us was the presence of obviously earlier capsules.  One had already dehisced and all were far more robust and distinctly different from the smaller red-striped hairy capsules of the currently flowering species.

On next to more Native Forest Reserves.  Once again the target species was Eriochilus but we were hoping to find among the flowers some colourful pink specimens.  It seemed this time we were a little too early because few flowers were seen.  However, a strong coloured pink flower was located and so became much photographed.  The next area was low open forest with bracken and heath understorey.  Showers caught up with us and lowered the visibility very considerably.  This made it hard to look for small greenhood type flowers but possible to find, once again Eriochilus sp.  Some lovely double headed flowers were seen but no leaves were evident.

At this early stage of the year it was amazing how many orchids were seen, albeit over quite a wide ranging area.  Perhaps some worthwhile early rains in the lower SE had been useful, but most of the species are not heavily dependent upon this for their Autumn appearance.